Results of orientation tests of nocturnal migrants with the use of Busses cage (Busse 1995, Busse 2000 are described in this paper. That method enables to study directional behaviour of nocturnal migrants during daytime. The aim of these studies is the description of directional preferences of the Robin and the Blackcap at the ringing station Arosio, northern Italy. Totally, 220 orientation tests for the Robin and 77 for the Blackcap were performed. Tested species have shown differentiation of directional preferences. Distribution of directions for the Robin is very clear. One direction was preferred SSE direction (34%). For the Blackcap the distribution of headings was more complex, but two main directions could be distinguished SSW (23%) and WSW (22%). Migration patterns of both these species in Europe are complicated. Birds migrating through northern Italy should be regarded as different migrating populations (Remisiewicz 2002, Mokwa 2004. However, migration pattern of the Robin was strongly determinated in one SSE direction, which indicates the Apennine Peninsula. Blackcap followed two directions, which indicate western winter quarters. Obtained results stood in accordance with other data, such as recoveries. Although the obtained results seem to be very interesting and promising, only intensive studies, especially in areas indicated by tested birds, could give information about migration pattern of these species.

Biometrics Variation and Directional Preferences of Immature Robins (Erithacus rubecula) Caught in Northern Italy during Autumn Migration in 2005 Inter-seasonal changes of biometry and preferred migration directions of Robins were studied according to data collected during autumn migration in northern Italy at the Arosio Bird Observatory (45°43'N, 9°12'E). Altogether 598 immature Robins were caught and 187 orientation tests were performed. Wing, tail and tarsus length, wing shape and weight were analysed in subsequent five migration waves distinguished according to migration dynamics. General pattern of migration as well as graphs with distribution of preferred directions in subsequent waves were prepared. In the case of tail length and weight their average values in subsequent waves were significantly different. Decrease of wing length was noted along the season. On the contrary, increasing trend was observed in the case of tail length and wing shape. Results of orientation tests showed that SSE direction was predominant (34%). SW direction was not clearly marked and its percentage was 23%. Distribution of directions slightly changed in subsequent migration waves. Noted results suggest passage of Robins heading to the Mediterranean basin and Apennine winter quarters. Obtained inter-seasonal changes of biometry and preferred directions can be an effect of differences in migration time between this groups or gradual inflow of more northern populations what the authors discuss here.

Intra-seasonal variation in the number of unmoulted coverts in immature Robins caught during 2001-2003 autumn migrations was studied at two ringing stations (Mierzeja Wilana and Bukowo-Kopañ) located at the Polish Baltic coast. To determine the number of unmoulted greater wing coverts we counted immature-type coverts with light spots at tips. In the analyses data on the number of spotted coverts from ca 11 000 migrating individuals were used. We analysed the number of spotted coverts in each season and at each ringing station separately. Based on migration dynamics we distinguished migration waves and the number of spotted coverts were compared among the waves. Trends of seasonal changes in mean values of this parameter were assessed. To explain these tendencies, percentage distributions of wing spots for each wave were presented, with distinguished three categories: 0-3 (low), 4-5 (medium) and 6-8 (high) number of spotted coverts. Next, we compared distribution of this parameter among waves by Kruskal-Wallis and post-hoc Dunns tests. Late waves generally differed in the distributions of spotted coverts number from the earlier ones in all seasons and at all stations. Our results showed the same tendencies within a season in all cases: the mean number of unmoulted coverts fluctuated in September, but starting from the end of this month and in October the trend was clearly increasing. This was due to changes in frequencies of Robins assigned to the distinguished categories in September birds with medium number of spotted coverts constituted over 50% of all migrants, while in late September and/or October waves individuals with high number of spotted coverts predominated. Both in 2002 and 2003, the moment of the shift in this domination from birds with medium to those with high number of unmoulted coverts was synchronised between the two stations. These intra-seasonal differences in moult advancement can be explained by two overlapping phenomena subsequent migration over the Baltic coast of populations with different moult characteristics and by less advanced moult of birds from later broods. Correspondence of the observed trends in moult advancement with literature data on migration timing of Robins of different breeding origin and winter quarters indicates that the populational differences play an important role in the observed variation.

Rosiñska K. 2007. Biometrics and morphology variation within sex-age groups of Robins (Erithacus rubecula) migrating through the Polish Baltic coast. Ring 29, 1-2: 91-106.Biometrical and morphological differentiation in sex-age groups of Robins migrating through the Polish Baltic coast was studied. Altogether 446 dead birds were collected in 1963-2004 during spring or autumn migration. Dead Robins were measured (wing and tail lengths and wing formula) and additionally in 2002-2004 leg colour and amount of grey colour on head and flanks were determined. After the measurements were taken, individuals were sexed by dissection.Birds were divided in four sex-age classes: immature females, immature males, adult females and adult males. Wing length, tail length, index of asymmetry (E) and pointedness (L) were compared among this classes using t-test. G-test was used to compare leg colour and greyness on head and flanks between the sexes for immature Robins. With a method of correlative topography charts showing combination of two parameters wing and tail lengths in different sex-groups of immatures were prepared.Obtained results indicate that sexes differ in wing and tail length and greyness on head and flanks. Males have longer wings and tails and bigger amount of greyness than females. The overlap of females and males is rather large, i.e. in the case of wing length 69-75 mm in immature and 71-74 mm in adult birds and in the case of tail length 55-67 mm in immature and 57-64 mm in adult birds. High probability of sex determination according to wing or tail length is found only in extremes. Combination of these two features only slightly increases possibility of sex determination.The Robin is a monomorphic species, therefore biometrical differences between males and females could be helpful in sexing. In some studies Robins were sexed according to criteria proposed by J. Pettersson referring to wing length, but only 29% of birds analysed here could be sexed when applying this criterion. These differences may result from varying composition of populations coming from different breeding areas. According to the charts presenting correlation between wing and tail length, three biometrical groups are distinguishable in both sexes.

The Wicie ringing station was one of several stations which cooperate within the SEEN organization (SE European Bird Migration Network). The station was located west of the small village of Wicie located in northern Poland on the central part of the Baltic Sea coast. The station was situated on a narrow spit between Kopañ Lake and the Baltic Sea and has operated since 2010. Data were collected during three spring and five autumn seasons. Birds were caught in mist-nets, which were placed mainly in bushes and reed beds. Over 55 000 birds of 113 species were caught and ringed during eight migratory seasons. Many of them were also tested for directional preferences in Busse’s cages.